Mary-Kate Parties After Heath's Death

Just before 8:30 p.m. on Jan. 24, a group of girls entered Pianos bar on NYC's Lower East Side. One of the girls, actress and entrepreneur Mary-Kate Olsen, started grooving to the band who had just taken the stage.

"She danced a little to their set," an eyewitness tells OK!. Just two days earlier, Olsen had made headlines in connection with actor Heath Ledger's untimely death. But on this night, witnesses say, "She didn't seem depressed. She was pretty much her normal self."

Perhaps Mary-Kate was trying to forget about the tragedy. After all, it was she who had received the first phone calls about Heath (four to be exact) from the actor's masseuse who said she'd found the Brokeback Mountain star unresponsive in his NYC apartment. Olsen reportedly sent her security team over right away and they showed up simultaneously with paramedics. Ledger was pronounced dead a short time later.

Those who know the 21-year old Full House star say she and Ledger,28, first met in the summer of 2006 when he was living at the Chateau Marmont in West Hollywood. Heath and Michelle Williams were starting to feel the strains on their relationship and Ledger warmed to the charms of Mary-Kate, who often hung out at the hotel with her twin, Ashley. "They were not dating but had hooked up in the past," a source tells OK!.

Despite their seven-year age gap, sources say Ledger and Olsen enjoyed similar interests — like partying. "MK liked nightlife. She liked to go to bars," the source tells OK!.

For the full story on Mary-Kate and Heath, pick up this week's OK! — on newsstands everywhere Thursday!